I still make my sites work in IE, down to IE4, and probably 1-3 too, I just haven't had a chance to test them yet.
I think that in the retro-computing world, IE will be one of the longest browsers still in use.
- no name-based virtual hosting (it does HTTP 1.0 but doesn't send Host headers)
- avoid redundant whitespace (it's not collapsed)
- wrap <style> and <script> contents in <!-- and // -->, otherwise they will be visible
I've had to keep an application's webinterface IE2 compatible ("usable") for longer than I wanted to as the initial configuration (opening up ports and IP addreses) was generally done on the NT4 server in IE itself.
(Once initial setup was done, further configuration could be done remotely with a more 'modern' browser, so fortunately only a few pages needed to be usable by IEs that old)
I will work to find an NT4 original ISO and get IE2 that way.
I've been doing the commenting thing, and found out that Mosaic treats >, not --> as the end of comment token, so I had to remove all > characters from my JS. :D